The performance of the solid-state memory (SSD) is prominently higher than that of traditional magnetic disk storage. Recently, the solid-state memory has been increasingly used in the personal computers (PC) and the notebook computers due to the reduction of the cost of the solid-state memory.
The storage medium in the solid-state memory itself is typically a NAND flash, and its metadata includes the fundamental information recorded on a hard disk, such as a logic-physical mapping table, management information of other hard disks, etc. The metadata is firstly loaded from the NAND flash to the random access memory (RAM) of the solid-state memory when the solid-state memory is powered on. During its operation, the reading/writing operations to the hard disk may simultaneously involve changes of the metadata (especially, the mapping table). In order to meet the speed requirements, these changes occur directly on the RAM, so that the metadata should be updated to the NAND flash timely. Otherwise, if an abnormality causing a power-off occurs, the metadata will be inconsistent with data, by which the SSD may not operate normally after it is repowered.
There is no approach in the prior art for recovering the metadata when the abnormality causing a power-off occurs.
Furthermore, conventionally, metadata information should be loaded when a SSD hard disk is powered on. Mapping table information in the metadata will be very large if a page mapping method is used, while the response time for the hard disk, when the power-on occurs, is long if the whole the metadata information is loaded.